Method for manufacturing a magneto-resistive effect element and a method for manufacturing a magneto-resistive effect type magnetic head

ABSTRACT

There is provided an MR manufacturing method comprising a film-forming process for forming a multilayer film including at least an antiferromagnetic layer  4 , a fixed layer  3  and a spacer layer  5 , a first patterning process for patterning the multilayer film after a predetermined pattern, a filing process for filling up the circumference of the patterned multilayer film, with an insulating layer  13  a process for forming a magnetic flux guide layer or a free layer also acting as the magnetic flux guide layer over this insulating layer  13  and the patterned multilayer film and a second patterning process by beam etching for simultaneously patterning the magnetic flux guide layer and the above-mentioned multilayer film to form the above-mentioned multilayer structure portion, wherein an incident angle of the etching beam are selected so that an angle θ of an etching surface relative to a normal is selected in a range of from 10°≦θ≦40°, preferably, 15°≦θ≦35°. Thus, etch rates of the materials composing the multilayer structure portion and materials compoising the insulating layer become nearly equal, whereby etchings at the respective portions can be achieved satisfactorily with high accuracy. As a result, characteristics of the magneto-resistive effect element and the magneto-resistive effect type magnetic head can be stabilized, and the yield thereof can be improved.

TECHNICAL FIELD

The present invention relates to a method of manufacturing amagneto-resistive effect element and a method of manufacturing amagneto-resistive effect type magnetic head.

BACKGROUND ART

In recent years, a recording density is progressively increased in thefield of the magnetic recording and magneto-resistive effect typemagnetic heads (MR type magnetic heads) using a giant magneto-resistiveeffect (GMR) element as a magnetic sensing portion are now put intopractical use. Lately, those magneto-resistive effect type magneticheads have achieved a recording density in excess of 50 Gb/inch² (e.g.,Intermag Conference 2000: Fujitsu, Read-Rite).

In such magnetic head, the MR element portion has a so-called CIP(Current In-Plane) type structure capable of detecting a magnetic fieldby an electrical resistance change occurring when a sense current isusually conducted in a film plane direction and an external magneticfield, i.e., a signal magnetic field corresponding to recordedinformation from a magnetic recording medium is applied to the filmplane in parallel thereto.

On the other hand, with the increasing demand for a higher recordingdensity, it has been requested that the elements are microminiaturizedby selecting materials composing the MR element portion which canrealize a high sensitivity and by using a high-precise patterning, to bespecific, a photolithography technique which can reduce a track width.

In contrast, as a magneto-resistive element which can exhibit a largerresistance change, there has been proposed based on a CPP (CurrentPerpendicular to Plane) type structure a spin valve type MR (SV typeGMR) element or a tunnel type MR (TMR) element in which a sense currentis conducted in the direction perpendicular to the film plane of the MRelement.

Of the MR element of this CPP type structure, the SV type GMR elementcan be realized by a film structure substantially similar to that of theconventional CIP type. Specifically, this magneto-resistive effectelement includes two ferromagnetic layers separated by a spacer layerformed of a thin nonmagnetic conductive layer and makes use of aresistance change based upon an electron spin dependent scatteringcaused on these interfaces.

In this case, one of the ferromagnetic layers is made of a materialwhose saturation coercive force is larger than that of the otherferromagnetic layer, and so has a high saturation magnetic field.

Further, in this structure, the film thicknesses of the respectivelayers are optimized depending on mean free paths of electrons in therespective layers so that the amount of the resistance change may beincreased.

The magnetic response of this MR element is a function depending upon arelative magnetization direction between the two ferromagnetic layers.

On the other hand, the TMR type element includes two ferromagneticlayers separated by a spacer comprised of a thin insulating tunnelbarrier layer and makes use of a resistance change caused by a magneticpolarization electron tunnel phenomenon.

One of these ferromagnetic layers has typically a saturation magneticfield which is higher than that of the other ferromagnetic layer in onedirection.

Then, its insulating tunnel barrier layer has a film thickness which isthin enough to make a quantum mechanics tunnel phenomenon occur betweenthe two ferromagnetic layers. This tunnel phenomenon depends upon anelectron spin, whereby a magnetic response of a tunnel type elementdepends upon a relative magnetization direction of the above-describedtwo ferromagnetic layers and a function of a spin polarity.

Because the SV type GMR element and TMR element in the CPP structurehave a still larger amount of resistance change as compared with that ofthe MR element in the above-mentioned CIP structure, a highly-sensitiveMR type magnetic head can be realized theoretically.

By the way, when data is recorded at a higher recording density, e.g.,100 Gb/inch², in order to detect narrow magnetic recording patternshaving a width less than 0.1 μm, it is requested to realize ahighly-precise MR element.

There has been proposed a method of manufacturing a microminiaturized MRelement as what element which can meet with such requirements.

In a method of manufacturing such a microminiaturized MR element,particularly, a MR element including a magnetic flux guide layer, themicrominiaturized MR element manufacturing process involves a processfor simultaneously patterning a portion having a multilayer film ofdifferent materials, particularly, a multilayer structure of aninsulating layer, e.g., aluminum oxide or silicon oxide and a metallayer, and a multilayer structure portion formed by a multilayer ofsubstantially only metal layers.

This patterning can be executed by ion beam etching method for example.In this case, because etch rates of aluminum oxide or the silicon oxideof the above-mentioned insulating layer and the metal layer areremarkably different from each other, there arises a problem that amicro miniaturized MR element having an aimed structure cannot bemanufactured with a satisfactory yield.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a method ofmanufacturing a magneto-resistive effect element and a method ofmanufacturing a magneto-resistive effect type magnetic head which cansolve the above-mentioned problem and can produce a microminiaturized MRelement having an aimed structure with high reliability.

A method of manufacturing a magneto-resistive effect element accordingto the present invention is a method of manufacturing amagneto-resistive effect element having a multilayer structure portionin which there are piled at least a magnetic flux guide layer, a freelayer made of a soft magnetic material of which there are piled themagnetization is rotated in response to an external magnetic field, orthe free layer also acting as the magnetic flux guide layer a fixedlayer made of a ferromagnetic material, an antiferromagnetic magneticlayer for fixing the magnetization of the fixed layer and a spacer layerinterposed between the free layer and the fixed layer, namely, an SVtype GMR multilayer structure portion or a TMR multilayer structureportion.

This manufacturing method comprises a film forming process for forming amultilayer film including at least the antiferromagnetic layer, thefixed layer and the spacer layer, a first patterning process forpatterning this multilayer film after a predetermined pattern, e.g., apattern having a predetermined depth length, a process for filling upthe circumference of the multilayer film thus patterned with aninsulating layer, a process for forming the magnetic flux guide layer orthe free layer also acting as the magnetic flux guide layer over thisinsulating layer and the patterned multilayer film, and a secondpatterning process for patterning simultaneously the magnetic flux guidelayer and the above-mentioned multilayer film after a predeterminedpattern, e.g., a pattern having a predetermined width to form theabove-mentioned multilayer structure portion by beam etching.

Moreover, according to the present invention, when the MR elementincluding the magnetic flux guide layer is formed, the first patterningfor determining the depth of the MR element body, i.e., theabove-mentioned SV type GMR multilayer structure portion or the TMRmultilayer structure portion and the second patterning for determiningthe widths of the MR element body and the magnetic flux guide layer areexecuted by etching in such a manner that the materials comprising theabove-mentioned multilayer structure portion and the materialscomprising the above-mentioned insulating layer at approximately equalthe same etch rate. This is done by selecting an incident angle of anetching beam. To be concrete, if the above-mentioned insulating layeris, e.g. silicon oxide, an angle θ relative to a normal of an etchedplane is selected in the range of 10°≦θ≦40°, preferably, 15°≦θ≦35°.

Furthermore, in the method of manufacturing the magneto-resistive effecttype magnetic head according to the present invention, themagneto-resistive effect element forming its magnetic sensing portion ismanufactured by the above-mentioned magneto-resistive effect elementmanufacturing method.

As described above, in the present invention, the SV type GMR multilayerstructure portion is, as it were, a metallic multilayer structureportion, whereas the TMR multilayer structure portion includes, e.g.aluminum oxide Al₂O₃ forming the tunnel barrier layer interposed as thespacer layer. However, this insulating layer is a extremely thininsulating layer having a thickness of about 0.6 nm, so that the TMRmultilayer structure portion has substantially a metallic multilayerstructure. For this reason, when the magnetic flux guide layer extendingover the metallic multilayer portion and the insulating layer is etchedtogether with the insulating layer, it is arranged that nearly equaletch rates are obtained by selecting the incident angle θ of the etchingbeam. This allows the etching depth of the above-mentioned multilayerstructure portion and its circumference to be made exactly equal.Therefore, the position of the hard magnetic layer which isbias-magnetized for the free layer that will be formed on this etchedportion later on can be determined with high accuracy.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A, 1B and 1C are a schematic plan view of an example of amagneto-resistive effect element obtained by a manufacturing methodaccording to the present invention and schematic cross-sectional viewtaken along the line B—B and a schematic cross-sectional views takenalong the line C—C, respectively.

FIGS. 2A, 2B and 2C are a schematic plan view of an example of amagneto-resistive effect type magnetic head obtained by a manufacturingmethod according to the present invention and schematic cross-sectionalviews taken along the line B—B and the line C—C, respectively.

FIGS. 3A, 3B and 3C are a schematic plan view showing one process of anexample of methods of manufacturing a magneto-resistive effect elementand a magneto-resistive effect type magnetic head according to thepresent invention, a schematic cross-sectional view taken along the lineB—B the line C—C, respectively.

FIGS. 4A, 4B and 4C are a schematic plan view of one process of anexample of methods of manufacturing a magneto-resistive effect elementand a magneto-resistive effect type magnetic head according to thepresent invention, a schematic cross-sectional view taken along the lineB—B and the line C—C, respectively.

FIGS. 5A, 5B and 5C are a schematic plan view showing one process of anexample of methods of manufacturing a magneto-resistive effect elementand a magneto-resistive effect type magnetic head according to thepresent invention, a schematic cross-sectional view taken along the lineB—B and the line C—C, respectively.

FIGS. 6A, 6B and 6C are a schematic plan view showing one process of anexample of methods of manufacturing a magneto-resistive effect elementand a magneto-resistive effect type magnetic head according to thepresent invention, a schematic cross-sectional views taken along theline B—B and a schematic cross-sectional view taken along the line C—C,respectively.

FIGS. 7A, 7B and 7C are a schematic plan view showing one process of anexample of methods of manufacturing a magneto-resistive effect elementand a magneto-resistive effect type magnetic head according to thepresent invention and schematic cross-sectional views taken along theline B—B and the line C—C, respectively.

FIGS. 8A, 8B and 8C are a schematic plan view showing one process of anexample of methods of manufacturing a magneto-resistive effect elementand a magneto-resistive effect type magnetic head according to thepresent invention and schematic cross-sectional views taken along theline B—B and the line C—C, respectively.

FIGS. 9A, 9B and 9C are a schematic plan view showing one process of anexample of methods of manufacturing a magneto-resistive effect elementand a magneto-resistive effect type magnetic head according to thepresent invention and schematic cross-sectional view taken along theline B—B and the line C—C, respectively.

FIGS. 10A, 10B and 10C are a schematic plan view showing one process ofan example of methods of manufacturing a magneto-resistive effectelement and a magneto-resistive effect type magnetic head according tothe present invention, a schematic cross-sectional view taken along theline B—B and the line C—C, respectively.

FIGS. 11A, 11B and 11C are a schematic plan view showing one process ofan example of methods of manufacturing a magneto-resistive effectelement and a magneto-resistive effect type magnetic head according tothe present invention and a schematic cross-sectional views taken alongthe line B—B and the line C—C, respectively.

FIG. 12 is a diagram for explaining a beam incident angle of a beametching in the present invention.

FIG. 13 is a diagram showing measured results of a relationship betweenthe beam incident angle of the beam etching and an etch rate in thepresent invention.

FIGS. 14A, 14B and 14C are a perspective view of a main part of an MRelement manufactured by a manufacturing method according to the presentinvention and cross-sectional view taken along the line B—B and across-sectional views taken along the line C—C, respectively.

FIGS. 15A, 15B and 15C are a perspective view of a main part of an MRelement of a comparative example and a cross-sectional views taken alongthe line B—B and a cross-sectional view taken along the line C—C,respectively.

FIGS. 16A, 16B and 16C are a perspective view of a main part of an MRelement of a comparative example and a cross-sectional views taken alongthe line B—B and the line C—C, respectively.

FIG. 17 is a schematic cross-sectional view of an example showing a dualtype MR element obtained by a manufacturing method according to thepresent invention.

FIG. 18 is a schematic perspective view showing an example of arecording and reproducing magnetic head using an MR type reproducingmagnetic head obtained by a manufacturing method according to thepresent invention.

BEST MODE FOR CARRYING OUT THE INVENTION

To begin with, a magneto-resistive effect element (MR element) MRobtained by a manufacturing method according to the present inventionand a magneto-resistive effect type magnetic head H using this MRelement as a magnetic sensing portion will be described with referenceto FIGS. 1 and 2.

The MR element and the magnetic sensing portion of the MR type magnetichead can be formed as the aforementioned SV type GMR structure or theaforementioned TMR structure.

FIGS. 1 and 2 show the MR elements and MR type magnetic heads both ofwhich have the so-called bottom type structures.

FIGS. 1A and 2A show schematic plan views of examples of MR elements andMR type magnetic heads obtained by the manufacturing methods accordingto the present invention. FIGS. 1B, 2B and FIGS. 1C, 2C are schematiccross-sectional views taken along the lines B—B and C—C of FIGS. 1A and2A, respectively.

AS shown in FIGS. 1A to 1C, the MR element includes a stripe-likemagnetic flux guide layer 1 which extends in a depth direction DPperpendicular to a track width direction Tw and whose front end 1 aserves as an end for introducing an external magnetic field, i.e., amagnetic field and to be detected. It also includes a multilayerstructure portion 6 which forms the MR element body at a limited portionon the front end 1 a side of this magnetic flux guide layer 1 or at alimited portion retreating from the front end 1 a in the depth directionby a required distance D. The magnetic flux guide layer 1 is superposedon the free layer 2.

This multilayer structure portion 6 includes a multilayer film formed bylaminating a free layer 2 made of a soft magnetic material of which themagnetization rotates in response to an external magnetic field, a fixedlayer 3 made of a ferromagnetic material, an antiferromagnetic layer 4for fixing the magnetization of this fixed layer 3 and a spacer layer 5interposed between the free layer 2 and the fixed layer 3.

On both sides of this multilayer structure portion 6 is located a hardmagnetic layer 7 in an opposing relation to at least both side end facesof the free layer 2 and the magnetic flux guide layer 1.

This hard magnetic layer 7 forms a permanent magnet magnetized so as toapply a bias magnetic field for erasing magnetic domains generated atboth ends of the free layer to improve Barkhausen noise which causes themagnetization in the free layer 2 to rotate discontinuously depending onthe external magnetic field.

These magnetic flux guide layer 1 and multilayer structure portion 6 aredisposed between first and second electrodes 11 and 12 to form the CPPstructure in which a sense current is conducted between the first andsecond electrodes 11 and 12 so that the sense current may be send to themultilayer structure portion 6 in a layer-piling direction, i.e. in thedirection crossing the film plane of each layer.

As shown in FIGS. 2A to 2C, the MR type magnetic head H uses theabove-mentioned magneto-resistive effect element MR as a magneticsensing portion which is disposed between first and second magneticshields 21 and 22.

Then, the surface of the front end 1 a of the magnetic flux guide layer1 facing outside is employed as a forward surface 8 which is a surfacein contact with or opposing to a magnetic recording medium. When thismagnetic head H is formed as a floating type magnetic head, e.g, as aslider located at the tip end of gimbals to be floated by the flow ofair produced due to the rotation of a magnetic recording medium such asa magnetic disk thereby producing a space between the head and thesurface of the recording medium, the above-mentioned forward surface 8serves as a so-called ABS (Air Bearing Surface).

While the first and second electrodes 11 and 12 as well as the magneticshields 21 and 22 are provided in the illustrated examples, each ofthese electrodes 11 and 12 can be united with each of magnetic shields21 and 22 can be modified as a magnetic shield also etching as theelectrode.

In FIGS. 2A TO 2C, elements and parts identical to those of FIGS. 1A TO1C are denoted by identical reference numerals and therefore theirrepeated explanations will be avoided.

When the above-mentioned multilayer structure portion 6 has the SV typeGMR structure, its spacer layer 5 is formed by a nonmagnetic conductivelayer. When the above-mentioned multilayer structure portion has the TMRstructure, the spacer layer is formed by a tunnel barrier layer made ofa nonmagnetic insulating layer.

While the magnetic flux guide 1 and the free layer 2 comprised ofindividual layers are shown 1A to 1C and 2A to 2C, in FIGS. The magneticflux guide and the free layer can be formed to have a freelayer/magnetic flux guide structure in which a manner that thestripe-like magnetic flux guide 1 itself forms the free layer 2 or as astructure in which the partial a thickness of the free layer serves asthe magnetic flux guide layer 1.

While, in the above illustrated example, the front end 1 a of themagnetic flux guide layer 1 opens on the forward surface 8 and themultilayer structure portion 6 of the MR element body forming, e.g. theSV type GMR or TMR element is disposed at the position retreated fromthe forward surface 8 in the depth direction DP by the required distanceD, the present invention is not limited thereto and this multilayerstructure portion 6 may be disposed at the position opening on theforward surface 8.

However, when the multilayer structure portion 6 is disposed at theposition opening on the forward surface 8, because characteristics ofthe MR element body, e.g., its shape and size will be determined in apolish and work process required to form the forward surface 8, thepolish and work process should be done with high accuracy, so thatdisadvantages such as fluctuations of characteristics, non-uniformcharacteristics and decreased yield cannot be avoided. Accordingly, theelement body, i.e., the multilayer structure portion 6 should preferablybe disposed at the position retreated from the forward surface 8 so thatthe magnetic flux guide layer 1 may introduce a external magnetic fieldto be detected, i.e., a magnetic flux.

Although an example of the method of manufacturing the MR element andthe MR type magnetic head will now be described with reference to FIGS.3A to 11C, it is needless to say that the manufacturing method accordingto the present invention is not limited to this example.

FIGS. 3A to 11A are schematic plan views. FIGS. 3B to 11B and FIGS. 3Cto 11C are cross-sectional views taken along the lines B—B and C—C inFIGS. 3A to 11A, respectively.

As shown in FIGS. 3A to 3C, a first electrode 11 is formed on asubstrate (not shown) made of AlTiC, for example. Then, a multilayerfilm 9 is formed by sequentially piling part of an antiferromagneticlayer 4, a fixed layer 3, a spacer layer 5 and a free layer 2 by meansof, e.g. magnetron sputtering or ion beam sputtering.

The first electrode 11 is formed of a conductive layer such as Ta, Auand Cu having a thickness of, e.g. about 3 nm to 20 nm.

The antiferromagnetic layer 4 is formed by piling films of PtMn, IrMn,RhMn, PdPtMn, NiMn and the like having thicknesses of, e.g. 6 nm to 30nm through buffer seed layers (not shown) of Ta, NiFe, Cu, and NiFeCrand the like.

The fixed layer 3 is made of a ferromagnetic material such as CoFe, NiFeand Co having a thickness of 2 nm to 10 nm and is formed so as to beexchange coupled with the antiferromagnetic layer 4.

This fixed layer 3 can be formed as a so-called multilayered ferri-layerstructure based upon an antiferromagnetic coupling in which a Ru layerof a nonmagnetic layer is interposed between multilayers, e.g., twolayers of, e.g. Co layers.

The spacer layer 5 is formed of a nonmagnetic layer made of Cu and thelike having a thickness of 2 nm to 5 nm for example, in the SV type GMRstructure. In the TMR structure, the spacer layer is formed of an Al₂O₃of natural Al oxide film or a plasma oxide film having a thickness of0.4 to 2.0 nm for example.

Further, the soft magnetic layer forming the free layer 2 or part of thefree layer 2 is formed of a single layer-or a multilayer film of Co,CoFe and NiFe having a thickness of 1 nm to 5 nm for example.

On this multilayer film 9, there is formed a first mask 10 serving as anetching mask and a lift-off layer, which will be described later, like astripe extending in the direction of track width Tw. This first mask 10can be formed by patterning a photoresist using the photolithography.Typically, through not shown, this mask 10 is formed of a double-layerresist having an undercut or a bridge-like resist so that the lift-offcan be executed satisfactorily.

Next, as shown in FIGS. 4A to 4C, using the first mask 10 as an etchingmask, the first patterning process is effected on the multilayer film 9,e.g. by ion beam etching. As a result, a first stripe portion SI whichhas a stripe shape extending in the track width direction after thepattern of the mask 10 is formed. The first stripe portion SI has arequired predetermined depth length L.

Next, as shown in FIGS. 5A to 5C, a recess or groove G1 surrounding themultilayer film 9 of the first stripe portion S1 formed by this etching,i.e., the first patterning process is buried with an insulating layer13, e.g. silicon oxide in the present invention, having a thicknesscorresponding to the thickness of the multilayer film 9. The insulatinglayer 13 is formed on the whole surface by a suitable means such asmagnetron sputtering or ion beam sputtering, and then the mask 10 ofFIGS. 4A to 4C is removed. By removing this mask 10, the insulatinglayer 13 on this mask 10 is removed, i.e. lifted off. Thus, theinsulating layer 13 fills up the circumference of the multilayer film 9,whereby the surface can be made flat.

As shown in FIGS. 6A to 6C, on this flat surface, a single film or amultilayer film of, e.g. Ni, Fe, Co, NiFe, CoFe having a thickness of 1nm to 10 nm is formed on the whole surface as the magnetic flux guidelayer 1.

As shown in FIGS. 7A TO 7C, on the magnetic flux guide layer 1, there isformed a second mask 14 having a stripe shape which extends in the depthdirection and intersects the first stripe portion S1 of the multilayerfilm 9.

This second mask 14 can be formed by the same method as that used toform the above-mentioned first mask 10.

In order that this second mask 14 may be formed in a predeterminedpositional relationship with the first stripe portion S1, an exposuremask in the photolithography used to form the second mask 14 isprecisely positioned with respect to an exposure mask in thephotolithography used to form the aforementioned first mask 10.

Note that, in this manufacturing method, the exposure masks areprecisely positioned with each other only when this second mask 14 isformed.

Then, in this positional matching, the stripe lengths of the two masksare selected so that the second mask 14 may securely intersect the areawhere the first mask 10 is formed.

Next, as shown in FIGS. 8A to 8C, using the second mask 14 as an etchingmask, there is formed a second stripe portion S2 having a predeterminedrequired rack width by effecting the second patterning process on themagnetic flux guide layer 1, and the multilayer film 9 and theinsulating layer 13 under the magnetic flux guide layer 1, e.g. by Arion beam etching.

In this manner, there is formed the multilayer structure portion 6having a small area of which the required depth length L is determinedby the first patterning process and of which the required width W thetrack width direction is determined by the second patterning process.

Particularly, the method according to the present invention ischaracterized by selecting an incident angle of this etching beam, inthis second patterning process, so that etch rates of all componentmaterials of the multilayer structure portion 6 including the magneticflux guide layer 1 may be approximately equal to an etch rate of siliconoxide of the component material of the insulating layer 13.

In this etching, as shown in FIG. 12, the above-mentioned etch rates canbe made nearly equal to each other by selecting an incident angle θ ofan ion beam b to an ion etched surface 31 (an angle to a normal 32 ofthe ion etched surface 31) in the range of 10°≦θ≦40°, preferably15°≦θ≦35°.

In this way, the first stripe portion S1 is etched to the predeterminedtrack width W, and the multilayer structure portion 6 having the SV typeGMR structure or the TMR structure made by piling of the magnetic fluxguide layer 1, the free layer 2, the spacer layer 5, the fixed layer 3and the antiferromagnetic layer 4 is formed only at a portion where thefirst and second stripe potions S1 and S2 cross with each other.

In this case, as described above, because the etch rates of theinsulating layer 13 made of the silicon oxide and the metal layers aremade approximately equal to each other, it is possible to preventstepped portions and the like from being produced when there exists adifference in the progress of etching is formed between the multilayerfilm 9 forming the structure portion 6 and the other portions.

Specifically, in an ordinary etching in which the ion beam is introducedfrom the vertical direction, as a table 5 shows examples of therespective materials and their etch rates, since the etch rate of theinsulating layer 13 made of silicon oxide is remarkably low comparedwith that of the metallic multilayer portion in the multilayer film 9.Thus, when the etching is satisfactorily executed in the multilayer film9 when the pattern of the multilayer structure portion 6 is formed, anetch residue is produced in the insulating layer 13. Thereafter, therearises a disadvantage when the hard magnetic film is formed on thisinsulating layer 13 as will be described later.

Next, a groove G2 surrounding the second stripe portion S2 formed bythis second patterning process is filled up. As shown in FIGS. 9A to 9Cthe insulating layer 13 made of silicon oxide and the hard magneticlayer 7 are sequentially formed to a thickness corresponding to thethickness of the stripe portion S2 by magnetron sputtering or ion beamsputtering. The second mask 14 of FIGS. 8A to 8C is removed and theinsulating layer 13 and the hard magnetic layer 7 on the second mask arelifted off. The surface is made flat in this manner.

The insulating layer 13 at this time is made of silicon oxide having athickness of, e.g. 5 nm to 20 nm and the hard magnetic layer 7 is madeof, e.g. Co—γFe₂O₃ with a high resistance or CoCrPt, CoNiPt, CoPt andthe like with a low resistance having a thickness of, e.g. 10 nm to 50nm. The hard magnetic layer 7 is and which is magnetized to form apermanent magnet.

In this case, the insulating layer 13 is formed so that the insulatinglayer may cover on the peripheral side surface of the multilayerstructure portion 6 to be interposed between the hard magnetic layer 7and the multilayer structure portion 6. Thus, even if the hard magneticlayer 7 is made of the above-mentioned low-resistance layer, themultilayer structure portion 6 and can electrically be insulated fromthe hard magnetic layer 7 by the insulating layer 13.

The position of the hard magnetic layer 7 with respect to a layer-pilingdirection of the multilayer structure portion 6 is set to be in apredetermined positional relationship with the free layer 2 and themagnetic flux guide layer 1 as will be described later.

Furthermore, as shown in FIGS. 9A to 9C, a third mask 15 which willserve as an etching mask and will be used in the lift-off later isformed by photo lithography using a photo resist similarly to theaforementioned respective masks, so as to cover the respective portionsof the stripe-like magnetic flux guide layer 1 and the hard magneticlayer 7 which are finally required.

Then, using this mask 15 as an etching mask, as shown in FIGS. 10A to10C, a portion of the hard magnetic layer 7 which is not covered withthis mask 15, a portion of the insulating layer 13 under the portion ofhard magnetic layer and the like are removed by etching.

Subsequently, as shown in FIGS. 11A TO 11C, an insulating layer 23 madeof silicon oxide or aluminum oxide and the like is formed so as to fillup a groove G3 formed by this etching and the insulating layer 23 on thethird mask 15 is lifted off by removing the third mask.

In this way, the surface is made flat and the second electrode 12 isformed on this flat surface by a suitable means such as sputtering.

Then, the wafer thus formed is cut, e.g. into each MR element along thesurface shown by a dot-and-dash line “a” in FIGS. 11A to 11C, and thedesired magneto-resistive effect element MR is obtained by grinding andprocessing the forward surface 8 which serves as a surface forintroducing an external magnetic field, i.e., a magnetic field to bedetected as shown in FIGS. 1A to 1C.

Moreover, in manufacturing when the magneto-resistive effect typemagnetic head H shown in FIGS. 2A to 2C, each of the first and secondelectrodes 11 and 12 shown in FIGS. 11A to 11C may be made to serve as amagnetic shield also. Alternatively, first and second magnetic shields21 and 22 (not shown) may respectively be made to the outer surfaces ofthe electrodes 11 and 12 to formed the so-called shield type structure.

As described above, the magneto-resistive effect element MR obtained bythe manufacturing method according to the present invention or themagneto-resistive effect type magnetic head H comprising this element MRhas the construction in which the multilayer structure portion 6disposed between the magnetic shields or the electrodes 11 and 12, as itwere, the element body is surrounded by the insulating material 13 andso insulated from the hard magnetic layer 7. Thus, even when a sensecurrent is conducted between the two electrodes 11 and 12 in a CPP typestructure, it is possible to avoid the leakage of the sense currentthrough this hard magnetic layer 7.

The hard magnetic layer 7 can stabilize the magnetic flux guide layer 1and the free layer 2 by applying the magnetic field from the permanentmagnet formed of this hard magnetic layer 7 to the magnetic flux guidelayer 1 and the free layer 2 along a track width direction. The magneticflux guide layer 1, the free layer 2 and the hard magnetic layer 7 aremagnetostatically coupled with one another magnetically. When the hardmagnetic layer 7 is conductive, the film thickness of theabove-mentioned insulating layer 13 interposed between those layers isselected to be so small that the insulating layer can insulate the hardmagnetic electrically.

As described above, because the MR element body, i.e., the multilayerstructure portion 6 structure in which it is buried into the insulatinglayer 13 in construction, the magnetic flux guide layer 1 can be incontact with the whole surface of the free layer 2 and can be extendedto the front portions and the rear or the rear portions of themultilayer structure portion 6.

When the free layer 2 of the MR element body is formed between the frontmagnetic flux guide and the rear magnetic flux guide, a magnetic flux tobe detected is introduced into the front end 1 a of the magnetic fluxguide layer 1, which is open on forward surface 8, attenuated throughthe free layer 2 serving as a detecting portion and lost at the end ofthe rear magnetic flux guide.

This means that, when the rear magnetic flux guide is provided, theamount of magnetic flux which passes the magnetic flux detecting portionincreases compared with the case where the rear magnetic flux guide isnot provided. As a result, the output signals from the SV type GMR typeand TMR type reproducing having the magnetic flux guide heads can beincreased. In short, it is to be understood that the magnetic flux guidelayer 1 is extremely important for realizing a high-sensitivity magnetichead.

Further, a space between the magnetic shields, i.e., a magnetic gaplength is selected depending upon a spatial resolution limited by atarget recording density of a magnetic head, e.g., in the range of 50 nmto 100 nm if a target recording density is 100 Gb/inch².

On the other hand, for example, the thickness of the second electrode11, and the like are selected so that the magnetic flux guide layer 1and the free layer 2 are located nearly at the center of the gap.

As described above, the manufacturing method according to the presentinvention aims to equalize the etch rates to each other by selecting thebeam incident angle θ of the ion beam etching in the second patterningprocess. This will be explained below. FIG. 13 shows measured results ofetch rates obtained when the incident angles θ of beam in the Ar ionbeam etching and materials of the etched layers are changed. In thisgraph, curves 16 a, 16 b and 16 c are such that measured results of etchrates relating to the multilayer film 9 in the SV type GMR structure,similar measured results relating to silicon oxide and similar measuredresults of etch rates relating to aluminum oxide are potted,respectively.

As is clear from these curves, when the silicon oxide is used as theinsulating layer 13 and, for example, the incident angle θ of the argonion beam, is selected in the range of 10° to 40°, a difference betweenthe etch rates of the multilayer film 9 and the silicon oxide film bemade to can be made to fall within the range of ±10%. Further, when theabove incident angle is selected in the range of 15° to 35°, theabove-mentioned difference can be made to fall within the range of ±5%.

The tables 1 to 4 show relationships among etch rates in the respectivematerial layers, the etching thicknesses of the respective layers andthe required etching time in the bottom the SV-GMR element, when theetching angle (beam incident angle) θ is selected to be −5°, −15°, −25°,−40°, respectively.

TABLE 1 Etching angle θ = −5° Etching Etching time Etch thicknessrequired Material Film name rate (nm/min) (nm) (min) NiFe Magnetic flux9 4 0.44 guide layer CoFe Free layer 9 1 0.11 Cu Spacer layer 15 2.50.17 CoFe Fixed layer 9 3 0.33 PtMn Antiferro-ma 12 15 1.25 gnetic layerTa Electrode 7 5 0.71 Total of above-mentioned all layers 30.5 3.02Silicon oxide Insulating 9 27.2 3.02 layer layer Aluminum Insulating 412.1 3.02 oxide layer layer

TABLE 2 Etching angle θ = −15° Etching Etching time Etch thicknessrequired Material Film name rate (nm/min) (nm) (min) NiFe Magnetic flux9 4 0.44 guide layer CoFe Free layer 9 1 0.11 Cu Spacer layer 16 2.50.16 CoFe Fixed layer 9 3 0.33 PtMn Antiferro-ma 12 15 1.25 gnetic layerTa Electrode 7 5 0.71 Total of above-mentioned all layers 30.5 3.01Silicon oxide Insulating 10.5 31.6 3.01 layer layer Aluminum Insulating4 12.0 3.01 oxide layer layer

TABLE 3 Etching angle θ = −25° Etching Etching time Etch thicknessrequired Material Film name rate (nm/min) (nm) (min) NiFe Magnetic flux11 4 0.36 guide layer CoFe Free layer 11 1 0.09 Cu Spacer layer 19 2.50.13 CoFe Fixed layer 11 3 0.27 PtMn Antiferro-ma 14 15 1.07 gneticlayer Ta Electrode 9 5 0.56 Total of above-mentioned all layers 30.52.49 Silicon oxide Insulating 12 29.8 2.48 layer layer AluminumInsulating 4.5 11.2 2.49 oxide layer layer

TABLE 4 Etching angle θ = −40° Etching Etching time Etch thicknessrequired Material Film name rate (nm/min) (nm) (min) NiFe Magnetic flux12 4 0.33 guide layer CoFe Free layer 12 1 0.08 Cu Spacer layer 22 2.50.11 CoFe Fixed layer 12 3 0.25 PtMn Antiferro-ma 15 15 1.00 gneticlayer Ta Electrode 10 5 0.50 Total of above-mentioned all layers 30.52.28 Silicon oxide Insulating 14 31.9 2.27 layer layer AluminumInsulating 5.5 12.5 2.27 oxide layer layer

TABLE 5 Etching angle θ = 0° Etching Etching time Etch thicknessrequired Material Film name rate (nm/min) (nm) (min) NiFe Magnetic flux8.5 4 0.47 guide layer CoFe Free layer 9 1 0.11 Cu Spacer layer 14.5 2.50.17 CoFe Fixed layer 9 3 0.33 PtMn Antiferro-ma 12 15 1.25 gnetic layerTa Electrode 7 5 0.71 Total of above-mentioned all layers 30.5 3.05Silicon oxide Insulating 8.2 25.0 3.05 layer layer Aluminum Insulating3.2 9.8 3.05 oxide layer layer

As is clear from FIG. 13 and the tables 1 to 4, when the insulatinglayer 13 is made of silicon oxide, the required etching time of themultilayer film 9 can be approximated to the required etching time ofthe insulating layer 13, even if the thickness of the silicon oxide isincreased. In contrast, when the insulating layer is made of aluminumoxide, the thickness of the aluminum oxide at which the required etchingtime can be approximated to that of the multilayer film 9 is too smallto fit practical use.

This is an example in which the magneto-resistive effect element has theSV type GMR multilayer structure. In the TMR multilayer structureelement, e.g. the aluminum oxide Al₂O₃, forming the tunnel barrier layeris interposed as the spacer layer. However, this insulation layer is anextremely thin insulation layer having a thickness of about 0.6 nm andso the TMR multilayer structure is substantially a metallic multilayerstructure. Thus, the etchings can be executed uniformly in such a mannerthat the etch rates are made approximately equal to each other byselecting the incident angle θ of the etching beam as well.

As mentioned before, in order to avoid a Barkhausen jump by removing themagnetic domains generated at the ends of the magnetic flux guide layer1 and the free layer 2, the product of the magnetic moment of thepermanent magnet formed of the hard magnetic layer 7 by its filmthickness must be made nearly equal to or larger than that of themagnetic flux guide layer 1 and the free layer 2. Because the magneticmoment of the hard magnetic layer 7 is generally smaller than those ofthe magnetic flux guide layer 1 and the free layer 2, a thickness of thehard magnetic layer 7 is selected to be considerably larger than thethose of the magnetic flux guide layer 1 and the free layer 2. Besides,in order that the bias magnetic field generated from the hard magneticlayer 7 may efficiently be applied to the magnetic flux guide layer 1and the free layer 2, at least end faces on the both sides of thesemagnetic flux guide layer 1 and free layer 2 must be placed in apositional relationship exactly opposite to the corresponding end faceof the hard magnetic layer 7.

FIGS. 14A to 14C shows a geometrical arrangement between the magneticflux guide layer 1 and the element body, i.e., the multilayer structureportion 6, which can satisfy the above-described conditions and the hardmagnetic layer 7 located on both outsides of the multilayer structureportion for applying a stabilizing bias magnetic field to the magneticflux guide layer 1 and the free layer 2. FIG. 14A is a perspective viewand FIGS. 14B and 14C are schematic cross-sectional views taken alongthe lines B—B and C—C in FIG. 14A.

In FIGS. 14A to 14C, FIG. 14C shows a positional relationship betweenthe hard magnetic layer 7 and the magnetic flux guide layer 1 in theforward surface serving as the introducing surface of the externalmagnetic field. FIG. 14B shows a positional relationship between thehard magnetic layer 7 and the magnetic flux guide layer 1 in the portionwhere the multilayer structure portion 6 of the MR element body islocated. As these figures show, the hard magnetic layer 7 and themagnetic flux guide layer 1 are formed so as to become flush with eachother.

In contrast, if the etch rate of the aforementioned insulating layer 13,e.g., Al₂O₃ or the like is considerably low unlike that of themultilayer film of the MR element body as FIG. 15A shows a perspectiveview and FIGS. 15B and 15C show schematic cross-sectional views takenalong the lines B—B and C—C in FIG. 15A, when the magnetic flux guidelayer 1 and the hard magnetic layer are flush with each other in FIG.15B, a stepped or level difference is produced in the multilayerstructure portion 6 of the MR element body as shown in FIG. 15C.

Therefore, such structure widens the magnetic gap length in the forwardsurface 8, so that the element spatial resolution is lowered.

When the hard magnetic layer 7 is made thin, in order to prevent theelement spatial resolution from being lowered, as FIG. 16A shows aperspective view and FIGS. 16B and 16C show schematic cross-sectionalviews taken along the lines B—B and C—C in FIGS. 1A TO 1C6A, the hardmagnetic layers 7 cannot be disposed at both outside ends of themultilayer structure portion 6 of the MR element body as shown in FIG.16B with the result that a stable sufficient response to the externalmagnetic field cannot be obtained.

In other words, in order to optimize the element spatial resolution andits operation stability, the same stabilizing bias must be applied tothe free layer and the magnetic flux guide of the element body. For thispurpose, the hard magnetic layer and the magnetic flux guide must bedisposed in the same geometrical arrangement.

When the etch rate of the multilayer structure portion 6 formed of themagnetic metal multilayer film is high, to stabilize both of the elementportion and the magnetic flux guide, the hard magnetic layer 7 must havean increased thickness as compared with the case of equal etch rates. Atthat time, the magnetic gap length at the tip, i.e., the front portionof the magnetic flux guide layer 1 which opens on the forward surfaceand the magnetic gap length at the rear portion of the magnetic fluxguide layer, located behind the multilayer structure portion 6 arewidened. As a result, the spatial resolution is lowered. When theelectrical insulating film for the magnetic flux guide is provided fromto avoid the loss in the current path between the upper and lowerelectrodes through the element portion, because the etch rate of theinsulating layer 13 provided on one of or both of the upper and lowersides of the magnetic flux guide layer 1 is selected to be nearly equalto that of the magnetic multilayer film in the multilayer structureportion 6, it is possible to prevent the operation stability and thespatial resolution from being deteriorated.

As described above, according to the manufacturing method of the presentinvention, the positional relationship among the hard magnetic layer 7,the magnetic flux guide layer 1 and the free layer 2 finally obtainedwhen the etch rates in the second patterning process are made equal toeach other can be arranged in a the satisfactory layout relationship.Therefore, the desired MR element and MR type magnetic head having thestable and uniform characteristics can be constructed.

Moreover, to improve the spatial resolution of the magnetic flux withrespect to the change of time in the shield type structure, it isimportant that the magnetic gap length defined by the magnetic shields21 and 22 at the front end of the magnetic flux guide layer 1 or in theforward surface 8 facing the multilayer structure 6 of the element bodyis kept constant over the whole track width.

As described above, providing the magnetic flux guide layer 1 enablesthe magnetic field under detection to be detected efficiently as theresistance change. In the manufacturing method according to the presentinvention, in order to manufacture the magneto-resistive effect elementand the magneto-resistive effect type magnetic head including thismagnetic flux guide layer there are performed the first patterning fordefining the depth length relative to the multilayer film forming theelement body and the second patterning in which the insulating layer 13for burying the portion formed by the first patterning and, the magneticflux guide layer are formed and the patterning of this magnetic fluxguide layer and the definition of the above-mentioned multilayer filmare executed at the same time.

In this method, exposure mask matching is performed substantially onlyonce when exposure masks used in the first and second patterningprocesses are matched with each other. With the above-mentionedarrangement, not only the manufacturing process can be simplified, butalso the element body of high accuracy pattern can be formed. In otherwords, data recorded at a high recording density, e.g. up to 100Gb/inch² can be reproduced, thus allowing the yield and reliability ofthe magneto-resistive effect element and the magneto-resistive effecttype magnetic head to be improved.

In this case, portions where the multilayer structure materials aredifferent from each other, in particular, a portion where the insulatinglayer 13 exits and a portion where the insulating layer does not existor hardly exists are simultaneously etched in the second patterning andbesides, the etch rate of the insulating layer is extremely low in theordinary method. Thus, a uniform etching is obstructed and theaforementioned disadvantage is inevitably brought about.

However, according to the method of the present invention, the etchrates can be made uniform by selecting the angle in this etching,whereby this problem can be solved.

While the multilayer structure portion 6 forming the MR element body hasthe bottom type of the SV type of GMR or TMR structure in theabove-mentioned example, the present invention is not limited to suchexample.

In addition, while the multilayer structure portion is formed as asingle type of the SV type GMR or TMR structure in the above-mentionedexample, the present invention can be formed as a dual type structure inwhich the free layers 2, the spacer layers 5, the fixed layers 3 and theantiferromagnetic layers 4 are respectively disposed on both surfaces ofthe magnetic flux guide layers 1 as shown in a schematic cross-sectionalview of FIG. 17. In this case, because since the magnetic flux guidelayer 1 and the free layers 2 are disposed at the central portion of themagnetic gap and a pair of the SV type GMR elements or TMR elements aredisposed, the output of the magne of FIGS. 4A to 4C to resistive effectelement can be enhanced.

Furthermore, since the magnetic head H according to the presentinvention is the magnetic head for reproducing recorded information fromthe magnetic recording medium, for example, a thin film type ofinduction type recording magnetic head can be superposed on the magnetichead H as one body to form a recording and reproducing magnetic head.

An example in this case will be described with reference to aperspective view of FIG. 18.

In this example, the magnetic head H manufactured by the above-mentionedmanufacturing method according to the present invention is formedbetween first and second magnetic shield also acting as electrodes 51and 52 on a substrate 41 and for example, a thin film magnetic recordinghead 130 of an electromagnetic induction type, is superposed on thesecond magnetic shield also acting as electrode 52, thereby allowing theabove magnetic head to be formed as the magnetic recording andreproducing head.

The recording head 130 has a nonmagnetic layer 131 made of SiO₂ and thelike forming the magnetic gap at its portion opening on the forwardsurface 8.

At the rear portion of this recording head, there is formed a coil 132,e.g. by patterning a conductive layer. An insulating layer covers thiscoil 132. The coil 132 has at its center a through-hole 133 boredthrough the insulating layer and the nonmagnetic layer 131 to expose thesecond shield also acting as electrode 52.

On the other hand, a magnetic core layer 134 is formed on thenonmagnetic layer 131, of which the front end opens on the forwardsurface 8 and which crosses the coil 132 and contacts with the secondshield also acting as electrode layer 52 that is exposed through thethrough-hole 133.

In this manner, there is formed the thin film recording magnetic head130 of the electromagnetic induction type in which the magnetic gap g,that is defined by a thickness of the nonmagnetic layer 131 is formedbetween the front end of the magnetic core layer 134 and the secondshield also acting as electrode layer 52.

On this magnetic head 130 is formed a protecting layer 135 made of aninsulating layer as shown by a dot-and-dash line.

In this way, there can be formed the recording and reproducing magnetichead in which the reproducing magnetic head H of the magneto-resistiveeffect type according to the present invention and the thin film typerecording head 130 are integrated as one body.

Note that the manufacturing method according to the present invention aswell as the MR element and the MR type magnetic head obtained by thismanufacturing method are not limited to the above-mentioned examples andthe present invention can be applied to the manufacturing process of MRelements and MR type magnetic heads having various structures andconstructions.

As described above, according to the manufacturing method of the presentinvention, in the manufacture of a high-output and high-sensitivitymagneto-resistive effect element including the magnetic flux guide layeras well as the magnetic head having the magnetic sensing portion formedby that element, the element body including the multilayer structureportion of the SV type GMR structure or TMR structure having therequired width and depth and further the magnetic flux guide layer canbe formed by the first patterning and the second patterning process forforming the insulating layer and aiming at uniform etch rates byselecting the incident angle of the etching beam. In particular, thepositional relationship of the hard magnetic layer relative to the freelayer and the magnetic flux guide layer can reliably be set into thepredetermined positional relationship advantageously.

Moreover, according to the method of the present invention, the exposuremasks are matched substantially only once in the mutual matching ofexposure masks used in the first and second patterning processes. Withthe above-mentioned arrangement, not only the manufacturing process canbe simplified, but also the element body of high accuracy pattern can beformed. Thus, data recorded at the high recording density, e.g. up to100 Gb/inch² can be reproduced thus allowing, the yield and reliabilityof the magneto-resistive effect element and the magneto-resistive effecttype magnetic head to be improved.

What is claimed is:
 1. A method of manufacturing a magneto-resistiveeffect element including a multilayer structure portion in which thereare laminated at least a magnetic flux guide layer, a free layer made ofa soft magnetic material of which the magnetization is rotated inresponse to an external magnetic field or said free layer also acting assaid magnetic flux guide layer, a fixed layer made of a ferromagneticmaterial, an antiferromagnetic layer for fixing the magnetization ofsaid fixed layer and a spacer layer interposed between said free layerand said fixed layer, said method of manufacturing saidmagneto-resistive effect element comprising: forming a multi layer filmhaving at least said antiferromagnetic layer, said fixed layer and saidspacer layer; patterning said multilayer film after a predeterminedpattern; filling up a circumference of said patterned multilayer filmwith an insulating layer; forming said magnetic flux guide layer or saidfree layer also acting as said magnetic flux guide layer over saidinsulating layer and said patterned multilayer film; and simultaneouslypatterning said magnetic flux guide layer and said multilayer film aftera predetermined pattern by beam etching, to form said multilayerstructure portion wherein said patterning is executed by such etchingthat etch rates of materials composing said multilayer structure portionand materials composing said insulating layer are made approximatelyequal by selecting an incident angle of an etching beam.
 2. A method ofmanufacturing a magneto-resistive effect element according to claim 1,wherein said insulating layer is composed of a silicon oxide film.
 3. Amethod of manufacturing a magneto-resistive effect element according toclaim 1, said incident angle of said etching beam is selected so that anangle θ relative to a normal of an etched surface may fall within therange of 10°≦θ≦40°.
 4. A method of manufacturing a magneto-resistiveeffect type magnetic head having a magneto-resistive effect element inwhich a magnetic sensing portion includes such a multilayer structureportion that there are laminated at least a magnetic flux guide layer, afree layer made of a soft magnetic material of which the magnetizationis rotated in response to an external magnetic field or said free layeralso acting as said magnetic flux guide layer, a fixed layer made of aferromagnetic material, an antiferromagnetic layer for fixing themagnetization of said fixed layer and a spacer layer interposed betweensaid free layer and said fixed layer, said method of manufacturing amagneto-resistive effect type magnetic head comprising: forming amultilayer film having at least said antiferromagnetic layer, said fixedlayer and said spacer layer; patterning said multilayer film after apredetermined pattern; filling up a circumference of said patternedmultilayer film with an insulating layer; forming said magnetic fluxguide layer or said free layer also acting as said magnetic flux guidelayer over said insulating layer and said patterned multilayer film; anda simultaneously patterning said magnetic flux guide layer and saidmultilayer film after a predetermined pattern by beam etching, to formsaid multilayer structure portion wherein said second patterning isexecuted by such etching that etch rates of materials composing saidmultilayer structure portion and of materials composing said insulatinglayer are made approximately equal by selecting an incident angle of anetching beam.
 5. A method of manufacturing a magneto-resistive effecttype magnetic head according to claim 4, wherein said insulating layeris composed of a silicon oxide film.
 6. A method of manufacturing amagneto-resistive effect type magnetic head according to claim 4,wherein said incident angle of said etching beam is selected so that anangle θ relative to a normal of an etched surface may fall within therange of 10°≦θ≦40°.